mainline inclusion
from mainline-5.4-rc1
commit 58c898ba
category: bugfix
bugzilla: 21614
CVE: NA

---------------------------

There are 4 users which check if queue is registered, so add one helper
to check it.

Cc: Christoph Hellwig <hch@infradead.org>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Reviewed-by: NYufen Yu <yuyufen@huawei.com>

Conflicts:
  block/blk-sysfs.c
  block/blk-wbt.c
Signed-off-by: NYu Kuai <yukuai3@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>